05 RS wagon idle dipping toward 500RPM

[Airboy]

My 1 week old RS stalled on me today while I was slowing down (clutch in) to turn into a parking lot. Prior to this, I have noticed that on occasion, while slowing down at stop lights, the tach would drop below the 500 mark (I am guessing that it is 500, one tick below that and it is "0") before rising back to ~750-800RPM. I can feel the engine shudder when this happens.

If I just let the car idle, the RPM is stable. If I take it up to say, third gear at 2500rpm and then clutch-in, the RPM would fall towards 500RPM before rebounding. This doesn't happen all the time though. When it happened today, the outside temperature is several degrees above freezing and it happened about 5minutes after the car was started.

I am taking it in to the dealership in a few days but wanted to check if anyone has come across this before. If it only happens while the engine is warming up, the dealership won't see it since they are 25min away...

p.s. does this car have electronic throttle?

video clip linked in post below, or here

update Jan 18,2005
After replacing Throttle body (incl IAC), TPS, MAF, and Oxygen Sensor w/o success, Subaru Canada is now arranging for a Technical guy to fly out here to Calgary and do more data logging with a laptop and "specialized software", or something like that.

At the rate things are going, this debugging process will stretch into most of February, or close to Four months

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[darioc]

it has a throttle cable. take it to the dealership so even if nothings wrong, down the road if something comes up youll still be covered by warranty. trust me. its worth your time. something is probably going on though. drop it off at night and let them look at it in the morning.

[OneOBS]

Take it in. It sounds like the IAC can't catch the RPM drop.

[west_minist]

I have this same behaviour with my EJ204 w/ AVCS and variable Intake.

But my own is an automatic.

Driving and braking hard or sudden stops dues it, or just rev the car and it will happen.

[bmorton]

Throttle control changed to electronic for MY2005. I haven't experienced this on my non-ETC 2004.

[dmatthew]

I'm going to check later to see if this happens to me

[Caplin 2.5]

my car dips toward 500rpm too and i have an 05 rs, but it only does that when my air conditioning is on. I just gas it alot to get it to go good.

[Airboy]

The darn thing stalled on me twice this morning. This happened about 5min into the commute. Shortly after, at a stop light, I noticed that the engine would idle at 500RPM. Drive a few more minutes, and the idle is back to normal, ~750.

Will be fun trying to explain this to the service writer and then have the correct info get to the mechanic. I can just picture it...drop it off in the morning, get call later saying nothing is wrong...

[dmatthew]

There is definitely something wrong there, can't you get a day off work to go to the dealership and then show them what's wrong with it?

[west_minist]

Tell me something, how do you come to a stop? Do you deaccelerate fast to a stop?

How far do your clutch have to go in before disengaging?

[Airboy]

Originally Posted by west_minist

Tell me something, how do you come to a stop? Do you deaccelerate fast to a stop?

How far do your clutch have to go in before disengaging?

I was crusing at ~70kph and then let off the gas to coast/slow down a little before pushing the clutch in (all the way) at ~2500rpm. The tach needle just kept going past the 500 mark and then the dash lights came on. I didn't really get the chance to hit the brakes yet...the car was still coasting when it stalled.

Hopefully this will get sorted out tomorrow.

[west_minist]

Ok. Let us know tomorrow what it is.

[JeffrWRX]

wierd.

Your car idles at 750RPMS???? Isn;t that high? My 04 RS idles right about 500 as does my roomates 2000 RS.

-Jeff

[Airboy]

Originally Posted by 25rs92029

wierd.

Your car idles at 750RPMS???? Isn;t that high? My 04 RS idles right about 500 as does my roomates 2000 RS.

-Jeff

The tach needle points to one tick below the "1" mark. I am assuming that this is the 750 mark. See the attached pic. Kind of confusing since two ticks below "1" is "0".

My Passat and Integra both idles ~700-800rpm.

[JeffrWRX]

I admit defeat...my car idles at 750 then. I feel stupid. I alwyas thought that mark was 500. Good luck with your car though!

-Jeff

[Airboy]

UPDATE Nov 1, 2004
Well, I kind of expected this to happen....dropped the car off in the morning, received call in afternoon from dealership saying they can't reproduce the problem.

Left it over night to make sure the engine is cold....still can't reproduce the problem. They observed that sometimes the RPM would dip to ~600 but that is "normal".

Over the weekend, the car didn't stall but on several occasions the RPM dipped to 500 again.

To top it all off, they "washed" my car. It looked like whoever was washing it wet it down and started wiping with a rag. There were scratches everywhere I could see patches of dirt on the body where the guy "missed" with his grit laden rag.

Do not let Centaur Subaru of Calgary wash your car!!

Time to try another shop I think.

[sandok]

I have the exact same problem on my Impreza 1.6LX. I went to two different shops and they did the same thing: cleaned up the throttle body and IAC valve. But the problem continues.

Does anyone know what the h...... ????

Thanks in advance.

[quantum]

Well, if the 05 2.5rs has a throtle position sensor (I just got mine so I don't know if they use some other means) maybe asking them to reset it will fix it. My old 94 jeep had that problem, my jeeps tps was bad, but usually a reset to factory settings will fix a low idle.

[Airboy]

I took some video clips of the idle problem. The 2.7MB file can be found here

The camera position on the later clips are quite bad due to the tripod shifting during the drive.

[95_Impreza]

My car does the same thing, however its a 1995 and an auto. I dont really know what to tell you other than rev it up. Thats what I do and mine fixes itself for a while

[Jejunum]

i have the same problem, erratic idle and occasional stall only when its cold.
2.5RS (2002), automatic

someone suggested (and seems to worK) by putting the key in the on position for a second before starting up you prime the fuel pump - dunno how true / valid it is though.

[ksubaru826]

This happens to my 04 RS but i have never had a problem with it ever stalling especially after i have been driving it

[SubaruImpreza_power]

My 1995 Impreza L does the samething when I start it up in the morning.

[Airboy]

Update in first post